Premium is simply an adjective that takes the user a step up from 'cool'. Whenever you feel like responding in conversation with a casual 'cool', take it up a notch and slip in a minty fresh 'premium' instead.

Zach: Norwood thinks he coined premium, but really he's just jealous of me for doing it first.
Joe: Premium, man. Norwood could never have made that up. Premium indeed.